1. Technical Field
The present invention relates to methods and apparatuses for biologic fluid sample analyses in general, and to those that selectively admix one or more reagents with a biologic fluid sample in particular.
2. Background Information
Biologic fluid sample (e.g., whole blood, urine, cerebrospinal fluid, body cavity fluids, etc.) analyses often require the addition of one or more reagents to the sample prior to the analysis. Analyses of substantially undiluted whole blood, for example, often include an amount of a reagent (e.g., a colorant) that facilitates constituent identification. The phrase “substantially undiluted” as used herein describes a sample which is either not diluted at all or has not been diluted purposefully, but has had some reagents added thereto for purposes of the analysis. To the extent the addition of the reagents dilutes the sample, if at all, such dilution has no clinically significant impact on the analysis performed.
There is considerable advantage for biologic fluid sample analysis systems and sample cartridges to have flexibility to perform multiple tests, including tests that utilize different reagents. For example, a first analysis may require the addition of a first reagent to a particular sample to enable a first analysis, and the addition of a second reagent to the same sample to enable a second analysis.
What is needed, therefore, is an apparatus and a method that is adapted to provide a plurality of reagents in small amounts that are easily handled and that can be selectively added to and mixed with sample prior to analysis thereof.